1. Field of the Invention
The present invention relates to an electrical signal taking-out device, and more particularly to an electrical signal taking-out device for taking out an electrical signal for measurement from a circuit portion mounted on electronic/electric equipment when the equipment is checked, adjusted, or repaired.
2. Description of the Background Art
In order to take out an electrical signal for measurement from a terminal of a small electronic component mounted on a printed electronic circuit board so as to check, adjust, or repair electronic/electric equipment, a signal input unit of measuring equipment and a unit from which the electrical signal for measurement is taken out have to be electrically connected together by an electrical signal taking-out device.
In a conventional electrical signal taking-out device, which is disclosed, for example, in U.S. Pat. No. 6,307,158, metal wires provided at distal ends thereof with grip portions for holding a terminal of the electrical signal taking-out portion of an electronic circuit are extended to a rear side of the device. The device is also provided at a middle portion thereof with a pulling/pushing mechanism using a spring or the like, wherein the metal wires are extended to the rearmost portion of the device so as to be connected with an input unit of measuring equipment via electric conductive wires.
Unfortunately, in the conventional device thus constructed, the length of the metal wires for achieving a holding function is ten to twenty times longer than a minimum length required for the holding function per se. However, with a remarkable advance in electronic technologies that has been made in the recent years, the longer the metal wires extending from a tip end of a probe of an oscilloscope via the electrical signal taking-out device and the like to a circuit terminal, the more external electromagnetic noise is picked up. Moreover, these metal wires or metal portions may serve as an electric circuit element on the way to connection, so that the measurement results may be significantly different from an original waveform and a proper value of the electrical signal. This hinders advance in measuring technologies.
The present invention has been made in view of the above problem. Accordingly, an object of the present invention is to provide an electrical signal taking-out device capable of obtaining measurement results analogous to an original waveform and a proper value of an electrical signal while suppressing influence of an external electromagnetic noise to the minimum.